The present invention relates to a ceramic member with electrodes used in ion flow control heads, encoders, scales, and high-precision electric field shutters.
A ceramic member comprising a flat plate having a plurality of minute through holes and having electrodes installed on one surface has been used in location detecting devices or recording devices as the part of ion flow control heads, encoders, scales, and high-precision electric field shutters.
An example of such a ceramic member used as part of an ion flow control head is shown in FIG. 3. As shown in FIG. 3, a ceramic member 7 has an electrode 1 provided on one surface. An ion source 5 is installed on the side opposite the surface on which the electrode 1 is provided. The ceramic member 7 controls the ejection of ions 2 to a dielectric drum 3 by switching the sign of charge carried by the electrode 1, so that the ejection of ions 2 through the minute through holes 4 is inhibited by making the electrode 1 carry a charge the same as that of the ions. By contrast, the ejection of ions is accelerated by making the electrode 1 carry a charge opposite that the ions carry. A rigid plate 9 supports the ceramic member 7 an ion flow control head 10, a line electrode 11, and a finger electrode 12.
However, since conventional ceramic members 7 have minute through holes 4 which have a constant area throughout the thickness direction of the ceramic member 7, the large resistance of passing particles results in poor ejection of particles, and the straight motion of particles is inhibited due to the collision of particles with the internal walls of the minute through holes.
To decrease the resistance of passing particles, the reduction of the thickness of the ceramic member has been one proposed solution. In this case, however, the manufacturing process becomes difficult, the mechanical strength of the ceramic member lowers, and the ceramic member may be damaged when minute through holes are formed.
Furthermore, when the above ceramic member 7 is used in an ion flow control head, since a dielectric drum 3 is installed on the side of the surface where the electrode 1 is provided, when the dielectric drum 3 is in close contact with the ceramic member 7, the electrode 1 becomes worn out due to the rotation of the dielectric drum 3.
Therefore, it is an object of the present invention to provide a ceramic member allowing for improved ejection of charged particles from the minute through holes, while maintaining high mechanical strength and good production efficiency. It is a further object of the present invention to provide a ceramic member having electrodes which do not wear out even if the drum is in close contact with the ceramic member.